(a) Field of the Present Invention
The bi-directional light emitting diode drive circuit in bi-directional power parallel resonance is disclosed by that a bi-directional power is used as the power source which is supplied to a first impedance which is constituted by a capacitive impedance component, or an inductive impedance component or a resistive impedance component as well as to a second impedance which is constituted by a capacitive impedance component and an inductive impedance component in parallel connection, whereby the inherent parallel resonance frequency of the second impedance is the same as the frequency of the bi-directional power source such as the frequency of an AC power, or the periodically alternated polarity power converted from the DC power to produce a parallel resonance status through the bi-directional power input. Thereof it is characterized in that the first impedance and the second impedance are series connected to receive a bi-directional power, whereby the power source voltage of the said bi-directional power is divided by the series connected first impedance and second impedance in parallel resonance to form a divided power for driving the bi-directional conducting light emitting diode.
(b) Description of the Prior Art
The conventional light emitting diode drive circuit using AC or DC power source is usually series connected with current limit resistors as the impedance to limit the current to the light emitting diode, whereof the voltage drop of the series connected resistive impedance always result in waste of power and accumulation of heat which are the imperfections.